Systems and methods for dry chemical reductant insertion in aftertreatment systems

Abstract

A reductant insertion system for an after treatment system configured to decompose constituents of an exhaust gas, includes: a dry reductant tank configured to contain a dry reductant; a reductant delivery line configured to operatively couple the dry reductant tank to the after treatment system for delivery of the dry reductant to the after treatment system; and a pressurized gas source configured to communicate the dry reductant to the after treatment system through the reductant delivery line using pressurized gas.

What is claimed is: 
     
       1. A reductant insertion system for an aftertreatment system configured to decompose constituents of an exhaust gas, comprising:
 a dry reductant tank configured to contain a dry reductant; 
 a reductant delivery line configured to operatively couple the dry reductant tank to the aftertreatment system for delivery of the dry reductant into a flow path of the exhaust gas flowing through the aftertreatment system; and 
 a pressurized gas source configured to communicate the dry reductant to the aftertreatment system through the reductant delivery line using pressurized gas, wherein the pressurized gas source comprises an exhaust gas recirculation line coupled to a first end of the reductant delivery line, the pressurized gas being recirculated exhaust gas; 
 a reductant communication line coupling the dry reductant tank to the reductant delivery line; and 
 a dry reductant feeder coupled to the reductant communication line and configured to communicate the dry reductant from the dry reductant tank to the reductant delivery line via the reductant communication line. 
 
     
     
       2. The reductant insertion system of  claim 1 , further comprising a valve disposed in the reductant delivery line, the valve configured to be selectively opened for communicating a predetermined volume of the dry reductant to the aftertreatment system. 
     
     
       3. The reductant insertion system of  claim 2 , further comprising a pressure sensor integrated with the valve. 
     
     
       4. A reductant insertion system for an aftertreatment system configured to decompose constituents of an exhaust gas, comprising:
 a dry reductant tank configured to contain a dry reductant; 
 a reductant delivery line configured to operatively couple the dry reductant tank to the aftertreatment system for delivery of the dry reductant into a flow path the exhaust gas flowing through the aftertreatment system; and 
 a pressurized gas source configured to communicate the dry reductant to the aftertreatment system through the reductant delivery line using pressurized gas, wherein the pressurized gas source comprises a compressed gas source coupled to the reductant delivery line and configured to provide compressed gas therethrough to the aftertreatment system; 
 a reductant communication line operatively coupling the dry reductant tank to the reductant delivery line; 
 a dry reductant feeder coupled to the reductant communication line and configured to communicate the dry reductant from the dry reductant tank to the reductant delivery line via the reductant communication line; and 
 an eductor coupled to the reductant delivery line downstream of the reductant communication line, wherein the pressurized gas source is coupled to the reductant delivery line via the eductor, the eductor configured to generate suction in the reductant delivery line for delivering the dry reductant to the aftertreatment system via the reductant delivery line; 
 wherein a first end of the reductant delivery line upstream of the reductant communication line is open to atmosphere. 
 
     
     
       5. The reductant insertion system of  claim 1 , further comprising a heater configured to heat the recirculated exhaust gas to a temperature sufficient to substantially decompose the dry reductant. 
     
     
       6. The reductant insertion system of  claim 1 , further comprising a valve coupled to the exhaust gas recirculation line and configured to be selectively opened for communicating the recirculated exhaust gas to the reductant delivery line. 
     
     
       7. A method for inserting dry reductant into an exhaust gas flowing through an aftertreatment system, the method comprising:
 determining an operating condition of the exhaust gas; 
 providing a pressurized gas to a reductant delivery line of a reductant insertion system, the reductant insertion system comprising:
 a dry reductant tank containing a dry reductant, 
 the reductant delivery line operatively coupling the dry reductant tank to the aftertreatment system, and 
 a pressurized gas source for providing the pressurized gas; and 
 
 activating a dry reductant feeder of the reductant insertion system to deliver the dry reductant into a flow path of the exhaust gas flowing through the aftertreatment system via the reductant delivery line; 
 wherein the pressurized gas source comprises a recirculated exhaust gas source. 
 
     
     
       8. The method of  claim 7 , further comprising:
 prior to providing the pressurized gas to the reductant delivery line, determining a temperature of the pressurized gas; and 
 in response to the temperature being less than a temperature threshold, heating the pressurized gas to a temperature sufficient to decompose the dry reductant. 
 
     
     
       9. The method of  claim 7 , wherein the dry reductant feeder comprises a screw feeder.